Direct polycondensation of N-trimellitylimido-L-isoleucine with aromatic diamines

N-Trimellitylimido-L-isoleucine (3) was prepared from the reaction of trimellitic anhydride with L-isoleucine [L-2-amino-3-methylvalerianic acid or (2S,3S)-2-amino-3-methyl-n-valerinic acid] in an N,N-dimethylformamide solution at the refluxing temperature. The direct polycondensation reaction of the monomer imide diacid (3) with 1,4-phenylenediamine, 4,4'-diaminodiphenylmethane, 4,4'-diaminodiphenylsulfone, diaminodiphenylether, 1,5-naphthalendiamine, 2,4-diaminotoluene, and 1,3-phenylenediamine was performed in a medium consisting of triphenyl phosphite, N-methyl-2-pyrolidone (NMP), pyridine, and calcium chloride. The polycondensation was performed under two different conditions: in one method, the reaction mixture was heated in an NMP solution at 60, 90, and then 130degreesC for different periods of time, and in the other method, the reaction mixture was refluxed only for 1 min in the same solvent. The resulting poly(amide imide)s (PAIs), with inherent viscosities of 0.21-0.37 dL/g, were obtained in high yields. All of these compounds were fully characterized by IR spectra, elemental analyses, and specific rotation measurements. Some structural characterizations and physical properties of these new optically active PAIs were examined. (C) 2003 Wiley Periodicals, Inc.